<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="./vue.js"></script>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        body {
            font: 15px/1.3 'Open Sans', sans-serif;
            color: #5e5b64;
            text-align: center;
        }

        a, a:visited {
            outline: none;
            color: #389dc1;
        }

        a:hover {
            text-decoration: none;
        }

        section, footer, header, aside, nav {
            display: block;
        }

        /*-------------------------
            菜鸟
        --------------------------*/

        nav {
            display: inline-block;
            margin: 60px auto 45px;
            background-color: #5597b4;
            box-shadow: 0 1px 1px #ccc;
            border-radius: 2px;
        }

        nav a {
            display: inline-block;
            padding: 18px 30px;
            color: #fff !important;
            font-weight: bold;
            font-size: 16px;
            text-decoration: none !important;
            line-height: 1;
            text-transform: uppercase;
            background-color: transparent;

            -webkit-transition: background-color 0.25s;
            -moz-transition: background-color 0.25s;
            transition: background-color 0.25s;
        }

        nav a:first-child {
            border-radius: 2px 0 0 2px;
        }

        nav a:last-child {
            border-radius: 0 2px 2px 0;
        }

        nav.home .home,
        nav.projects .projects,
        nav.services .services,
        nav.contact .contact {
            background-color: #e35885;
        }

        p {
            font-size: 22px;
            font-weight: bold;
            color: #7d9098;
        }

        p b {
            color: #ffffff;
            display: inline-block;
            padding: 5px 10px;
            background-color: #c4d7e0;
            border-radius: 2px;
            text-transform: uppercase;
            font-size: 18px;
        }

    </style>
</head>
<body>
<div id="main">
    <nav v-bind:class="active" v-on:click.prevent>
        <a href="#" class="home" v-on:click="makeActive('home')">Home</a>
        <a href="#" class="projects" v-on:click="makeActive('projects')">Projects</a>
        <a href="#" class="services" v-on:click="makeActive('services')">Services</a>
        <a href="#" class="contact" v-on:click="makeActive('contact')">Contact</a>
    </nav>
    <p>您选择了：<b>{{active}}</b></p>
</div>
    <script>
        new Vue({
            el: "#main",
            data: {
                active: "home"
            },
            methods: {
                makeActive: function (item) {
                    this.active = item
                }
            }
        })
    </script>
</body>
</html>